The present invention relates to disk drives of the type that accept removable disk cartridges. More particularly, this invention relates to an improved disk drive that has an improved system for and method of ejecting a disk cartridge from a disk drive, an improved system for and method of retracting and holding the read/write heads of a disk drive in a retracted position, an improved system of and method for operating an eject system and a retraction system of a disk drive and an improved system for and method of loading a motor for engaging a hub of a disk cartridge.
Disk drives for storing electronic information are found in a wide variety of computer systems, including workstations, personal computers, and laptop and notebook computers. Such disk drives can be stand-alone units that are connected to a computer system by a cable, or they can be internal units that occupy a slot, or bay, in a computer system. Laptop and notebook computers have relatively small bays in which to mount internal disk drives and other peripheral devices, as compared to the much larger bays available in most workstation and personal computer housings. The relatively small size of peripheral bays found in laptop and notebook computers, can place significant constraints on the designer of internal disk drives for use in such computers. Techniques that address and overcome the problems associated with these size constraints are therefore important.
Disk drives of the type that accept removable disk cartridges have become increasingly popular. One disk drive product that has been very successful is the ZIP(trademark) drive designed and manufactured by Iomega Corporation, the assignee of the present invention. ZIP(trademark) drives accept removable disk cartridges that contain a flexible magnetic storage medium upon which information can be written and read. The disk-shaped storage medium is mounted on a hub that rotates freely within the cartridge. A spindle motor within the ZIP(trademark) drive engages the cartridge hub when the cartridge is inserted into the drive, in order to rotate the storage medium at relatively high speeds. A shutter on the front edge of the cartridge is moved to the side during insertion into the drive, thereby exposing an opening through which the read/write heads of the drive move to access the recording surfaces of the rotating storage medium. The shutter covers the head access opening when the cartridge is outside of the drive, to prevent dust and other contaminants from entering the cartridge and settling on the recording surfaces of the storage medium.
The ZIP(trademark) drive is presently available for workstations and personal computers in both stand-alone and internal configurations. In order to provide a version of the ZIP(trademark) drive for use in laptop and notebook computers, the size constraints of the peripheral bays of such computers must be considered. In particular, for an internal drive to fit in the majority of laptop and notebook peripheral bays, the drive must be no longer than 135 mm. The height of the drive must be in the range of 12 to 15 mm. These dimensions place many constraints on the design of such a drive, and give rise to numerous design problems. The present invention addresses and overcomes some of the problems presented in designing a disk drive to these specifications.
A disk drive typically includes an actuator that has heads for interfacing with a disk cartridge, a head retraction system for moving these heads to a retraced position, an eject system for ejecting a disk cartridge from the disk drive and an operating system for powering the head retraction system and the eject system. By way of background a general overview of the operation of a disk drive employing these features is provided.
A disk cartridge is inserted into the disk drive. In order to remove the disk cartridge from the drive, an eject button disposed on the periphery of the drive is typically depressed. This button causes the operating system to power the head retraction system. When powered, the head retraction system causes the heads to move away from the disk cartridge and into a retracted position. After the heads have been retracted the operating system powers the eject system and ejects the disk cartridge from the disk drive.
Due to the limited length and height of a disk drive designed to be incorporated into a lap top computer, each of these systems must operate in a relatively small volume. Furthermore, many of the known prior art systems cannot be integrated into a disk drive having these limitations. While the eject system, head retraction system, operating system and motor loading system are advantageous for their intended applications, there is a need for improved systems that can be implemented in lower profile disk drives, such as that described above. The present invention satisfies these needs.
An improved disk drive includes an improved operating system, an improved eject system, an improved head retraction system and an improved motor loading system.
An improved operating system for a disk drive includes a motor, a head crank, an eject crank and an actuator. The actuator selectively links the output of the motor to either the head crank or the eject crank. When powered, the head crank causes the heads to be retracted from the disk cartridge and move to a retracted position. In the retracted position the likelihood of damage to the heads is decreased.
Similarly, the eject crank can be powered by the output of the motor to eject a disk cartridge from the disk drive.
The actuator selectively controls the output of the motor by moving between a first position and a second position. In a first position, the output of the motor is linked to the eject crank. When activated, the actuator functions to direct the output of the motor to a second position where it is linked to the head crank. In this position, the motor will cause rotation of the head crank and operation of the heads. After the heads have been retracted, the activator functions to couple the output of the motor back to the first position and to power the eject crank. When powered, the eject crank functions to eject a disk cartridge from the disk drive.
In a preferred embodiment of this invention, the output of the motor is linked to a gear train that can be selectively controlled by the actuator to be directed to either the eject crank or the head crank. Included within this gear train may be an output gear to which either an eject gear disposed on the eject crank or a head gear disposed on the head crank may be selectively connected. This gear train provides a gear reduction so that the proper torque and speed of the eject crank and the head crank can be achieved.
The actuator may be an electro-mechanical device that responds to signals from a typical central processing unit to selectively direct the output of the motor to either the eject crank or the head crank. Alternatively, the actuator may be a purely mechanical device that provides forces that operate with the force exerted by the rotation of the motor to switch the output of the motor between the eject crank and the head crank.
An improved head retraction system includes a drive link and a trolley that operate in conjunction with a spring and a head crank to retract the heads from a disk cartridge. The heads are preferably mounted on a carriage assembly that rides in a groove of a retainer. In a preferred embodiment the trolley engages a post extending from the carriage assembly to hold the carriage assembly to the retracted position. The head crank is preferably operated by the improved operating system described above to move the trolley to a spring loaded position. Power from the head crank is then removed and the trolley is driven by spring pressure to contact the post of the carriage assembly and hold it in the retracted position.
In a preferred embodiment, the head crank has a capture feature that captures a wire that links the head crank to a drive link. The drive link is coupled to the trolley to link the head crank to the trolley. The capture feature includes a groove disposed around a portion of the periphery of the head crank and a recess in the head crank. The wire preferably has a shaped end that can mate with the recess. As the head crank rotates, the wire acts as a cam because it is attached to the periphery of the head crank.
An improved eject system preferably includes a specially shaped eject lever, a drag link and an eject crank. The eject lever is rotatably mounted to the disk drive and spring biased to an unloaded position. The drag link may be translatably mounted to the disk drive and it interfaces with the eject lever. The drag link is also spring biased. The drag link interfaces with the eject crank to transmit movement of the eject crank to movement of the eject lever.
In particular, the eject lever is rotated by a spring to an unloaded position when a disk cartridge is not inserted. In this position, the eject lever holds the drag link against spring pressure in a spring loaded position. Upon inserting a disk cartridge into the disk drive, the disk cartridge drives the eject lever to rotate against spring pressure. When it rotates, the eject lever releases the drag link, which then moves due to the force of the spring pressure. After the drag link has been moved, it holds the eject lever in its rotated position against spring pressure.
When an eject button disposed on the disk drive or similar input device is depressed, the microprocessor operates to power the operating system and rotate the eject crank. When the eject crank rotates, it engages the drag link and moves it against spring pressure. As the drag link rotates, it releases the eject lever which rotates due to spring pressure. The rotation of the eject lever drives the disk cartridge from the disk drive. As the eject lever rotates, it engages the drag link and holds it in its spring loaded position.
The eject lever may have a specific shape. For instance, it may be mounted so that it has a portion above the chassis of the disk drive and a portion below the chassis. A single piece is used to allow for the efficient transmission of torque between the two surfaces. In a preferred embodiment, the eject lever is inserted through an aperture in the chassis and it has a pair of sealing flanges to prevent dust or contaminants from being transmitted through the aperture. One of the sealing flanges is disposed above the chassis and the other is disposed below the chassis. As the eject lever is rotated, the sealing flanges operate in conjunction to prevent the aperture from becoming uncovered, and they thereby seal the aperture from dust and other contaminants.
According to another aspect of this invention, it employs a motor loading system. This motor loading system permits the moving of a disk drive motor between an unloaded and a loaded position. In the loaded position the disk drive motor engages a disk cartridge to rotate a storage medium disposed in the cartridge for retrieving from and storing information on the storage medium.
The disk drive motor of this motor loading system may have a threaded exterior. The threaded exterior may be a threaded ring running around the circumference of the disk drive motor. Additionally, this motor loading system may include an aperture in the chassis of the disk drive that has a threaded ring running around the circumference of the aperture. The disk drive motor can be inserted into this aperture. Upon insertion, the threads disposed on the disk drive motor can be mated with those disposed on the threaded motor ring to cause the disk drive motor to be driven towards the chassis.
The chassis may have a spring extending from the threaded ring, and the disk drive motor may have a member extending from its periphery for interfacing with the eject system. This member couples the disk drive motor to the eject system so that the disk drive motor can be moved between an unloaded and a loaded position when a disk cartridge is respectively ejected and inserted into the disk drive.
When inserting the disk drive motor into the aperture, the member can engage a component of the eject system. This component may be a post extending from the drag link. Upon inserting the disk drive motor, the member may depress the spring. The disk drive motor can then be rotated to mate the threads of the disk drive motor with the threaded ring. When rotated, the member releases the spring.
The spring functions to prevent rotation of the disk drive motor past a predetermined point and thereby prevents the motor from becoming dislodged from the chassis due to mechanical shock or other forces.